1. Field of the Invention
The present invention relates generally to agents which inhibit or interfere with cellular redox systems as well as to the utilization of these agents as diagnostic tools and/or therapeutic agents. More specifically, the present invention relates to agents which interfere with or inhibit a thioredoxin/thioredoxin reductase redox system.
2. Background of the Related Art
Cellular redox systems appear to be very important to normal cellular activity. Cells maintain an intracellular environment that is reducing in the face of a highly oxidizing extracellular environment. Regulated alterations in the intracellular redox state (redox signaling) can modulate events such as DNA synthesis, enzyme activation, selective gene expression, regulation of cell cycle, cell growth, and programmed cell death.
One of the more important consequence of intracellular redox signaling is a change in the oxidative state of select cysteine residues on certain proteins. The post-translational modification of cysteine is difficult to follow since it lacks a convenient marker and is readily reversed when the cell contents are exposed to extracellular oxidizing conditions.
One type of abnormal cell function is abnormal cellular proliferation. Abnormal cellular proliferation is a cardinal feature of human malignancy. During the past decade there has been much insight into the biomolecules that regulate cell proliferation and the pathways in which they operate. These biomolecules have been identified as pharmacological, therapeutic, and/or diagnostic targets for agents which inhibit cellular proliferation.
Another type of abnormal cell function is resistance to apoptosis. Apoptosis is a form of programmed cell death characterized by membrane blebbing, chromatin margination and breakdown of chromosomal DNA into nucleosome-sized fragments. Programmed cell death or apoptosis is an important event in the normal processes of development and tissue remodeling. Loss of apoptosis can lead to diseases associated with cellular proliferation, such as cancer autoimmune disease, inflammation and hyperproliferation disease, while increased apoptosis can lead to neurodegenerative disease and destruction of tissue, as well as cardiovascular damage. Normally, when a cell sustains substantial genetic damage that cannot be repaired by normal DNA repair processes, this is recognized by sensory mechanisms in the cell and a sequence of events is initiated which leads to the death of the cell. Apoptosis results in the death of individual damaged cells and protects the organism from potentially harmful genetic changes that could lead to unregulated cell growth including cancer. Apoptosis resistance has been correlated with induction of the cylcin-dependent kinase inhibitor. There are now documented instances where inhibition of apoptosis by the abnormal expression of an oncogene or the loss of a tumor suppresser genes are closely associated with malignancy. It also appears that as cells develop from a nontransformed state, through a pre-malignant to a fully transformed state, they progressively lose their ability to undergo apoptosis. Apoptosis is also inhibited by some viral infections, in auto immune disease and hyperproliferative skin diseases.
Discovery of molecules which interfere with or inhibit cellular redox systems satisfies a need in the art by providing new diagnostic or therapeutic compositions useful in the detection, prevention, and treatment of diseases related to abnormal cellular activity (i.e., proliferation and apoptosis). These diseases include cancer, viral and other infections, inflammatory diseases, cardiovascular disease, nuerodegenerative diseases, skin disease and immunological disorders.
Proteins and enzymes involved in the cellular redox reaction provide an attractive site for the development of therapies, diagnostic, and assays for diseased states associated with abnormal cellular function. These agents may serve as chemotherapeutic agents themselves or may increase the efficacy of existing chemotherapeutic agents. Because of the close interactions between intracellular signaling pathways for proliferation and death, effective and selective inhibitors of cell proliferation may also cause desirable cell death.
Strategies for targeting redox related processes in the development of anticancer therapies can be subdivided into three main areas. First, there has been considerable activity in the exploitation of the hypoxic nature of solid tumors. Leading this charge is the search for bio-reductive drugs which will be metabolically activated in the hypoxic fraction. This effort has included the search for agents which will modify (both increase and decrease) the hypoxic fraction. A second approach attempts to alter enzyme levels or activities through gene therapy or induction by non-toxic agents. Finally, cellular signaling pathways having points of redox control have become the target of therapeutic or chemopreventitive intervention. Inhibitors of cellular redox or agents which interfere with cellular redox have strong potential applications as chemopreventative or chemotherapeutic agents.
The present invention is directed to inhibitors of redox signaling and a method of using these inhibitors for therapeutic or prophylactic treatment of a mammalian host caused by abnormal cellular function. The inhibitor(s) may be administered alone or in combination with other thereapeutic agents (e.g. other anti-cancer drugs).
This invention relates to a composition comprised of an inhibitor of cellular redox signaling, along with a pharmaceutically acceptable carrier of said inhibitor. It is preferable that the inhibitor(s) of cellular redox signaling also prevent inhibition of apoptosis. Preferably the inhibitor of cellular redox signaling inhibits or interferes with a thioredoxin redox system, and more preferably, the inhibitor of said thioredoxin system is an inhibitor of thioredoxin or an inhibitor of thioredoxin reductase.
The present invention also relates to a composition comprising or including an said inhibitor of cellular redox signaling with an IC50 TR/Trx of less than about 50 xcexcg/ml. Preferably the inhibitor of cellular redox signaling has an IC50 TR/Trx of less than about 25 xcexcg/ml, more preferably an IC50 TR/Trx of less than about 10 xcexcg/ml, even more preferably an IC50 TR/Trx of less than about 5 xcexcg/ml, and most preferably the inhibitor of cellular redox signaling has an IC50 TR/Trx of less than about 1 xcexcg/ml.
Preferably the inhibitor of cellular redox signaling is selected from the group consisting of NSC 401005, NSC 208731, NSC 382000, NSC 665103, NSC 617145, NSC 618605, NSC 622378, NSC 620109, NSC 163027, NSC 131233, NSC 665102, NSC 631136, NSC 681277, NSC 140377, NSC 603084, NSC 382007, NSC 635002, NSC 620358, NSC 657028, NSC 661221, NSC 622188, NSC 645330, NSC 350629, NSC 102817, NSC 626162, NSC 655897, NSC 267461, NSC 627124, NSC 610187, NSC 624982, NSC 664951, NSC 277293, NSC 608972, NSC 634761, NSC 664271, NSC 665878, NSC 625814, NSC 264054, NSC 652257, NSC 661225, NSC 637828, NSC 647546, NSC 655305, NSC 641396, NSC 668262, NSC 662781 and NSC 626678.
The present invention also relates to a composition comprised of a therapeutically effective amount of an agent which inhibits cellular redox signaling wherein the agent also prevents inhibition of apoptosis. Preferably the agents has an IC50 TR/Trx in the range of about 10 xcexcg/ml to about 25 xcexcg/ml, more preferably an IC50 TR/Trx in the range of about 5 xcexcg/ml to about 10 xcexcg/ml, even more preferably an IC50 TR/Trx in the range of about 1 xcexcg/ml to about 5 xcexcg/ml, and most preferably in a range of about 0.0001 xcexcg/ml to about 1 xcexcg/ml.
The invention also relates to a composition comprised of an inhibitor of cellular redox signaling and a pharmaceutically acceptable carrier, wherein the inhibitor of cellular redox signaling is selected from the group consisting of NSC compounds identified herein and preferably wherein the inhibition is in a therapeutically effective amount.
The therapeutically effective amount is preferably in a range from about 0.05 mg/kg/day to about 5,000 mg/kg/day, more preferably in a range from about 0.5 mg/kg/day to about 500 mg/kg/day, more preferably in a range of about 1 mg/kg/day to about 50 mg/kg/day, and more preferably yet, the therapeutically effective amount is in a range from about 2 mg/kg/day to about 20 mg/kg/day, and most preferably the therapeutically effective amount is in a range from about 5 mg/kg/day to about 10 mg/kg/day.
The invention also relates to a composition for treating a disease comprised of an inhibitor of cellular redox signaling in a dose effective in treating said disease. The disease is preferably related to redox function and more preferably related to abnormal cellular proliferation and/or abnormal apoptosis. The disease is preferably selected from the group consisting of cancer, reperfusion injury following ischemia, hepatitis, amyetrophic lateral sclerosis, neurodegenerative diseases, Alzheimers diseases Autoimmune disease, Sjogren""s syndrome, Lupus, rheumatoid arthritis, HIV, Hermansky-Pudlack syndrome, retinal oxidative damage, retinopathy, skin hyperplasia, aging, ultraviolet damage, wound healing, Crohns"" disease, ulcerative colitis, angiogenesis, uterine disorders, adult respiratory distress syndrome (ARDS), lung disorders, viral and other infections such as herpes virus, pox virus and adenovirus infections, inflammatory conditions, automimmune diseases such as, systemic lupus erythematosus, rhematoid arthritis, psoriasis, inflammatory bowel disease and autoimmune diabetes, immune mediated glomerular nephritis, hyperproliferative diseases such as fibrosis, psoriasis and mycosis fungoides. It is preferable that the inhibitor of cellular redox signaling inhibits thioredoxin activity which is associated with thioredoxin and thioredoxin reductase.
This invention also relates to a method of inhibiting growth in a cell comprised of contacting the cell with an effective amount of an inhibitor of redox activity, wherein the inhibitor of redox activity is an inhibitor of a thioredoxin/thioredoxin reductase redox system, and even more preferably wherein said agent prevents inhibition of apoptosis. It is preferable that the inhibitor of cellular redox signaling has an IC50 TR/Trx of less than about 50 xcexcg/ml, preferably less than about 25 xcexcg/ml, more preferably less than about 10 xcexcg/ml, even more preferably an IC50 TR/Trx of less than about 5 xcexcg/ml, and most preferably the inhibitor of cellular redox signaling has an IC50 TR/Trx of less than about 1 xcexcg/ml. Preferably, the inhibitor of cellular redox signaling is selected from the group of NSC compounds referred to herein.
The growth in a cell is inhibited with an effective amount of inhibitor which may be based on the effectiveness of previously identified active inhibitors. Preferably, the therapeutically effective amount is in a range from about 0.01 mg/kg/day to about 500 mg/kg/day. More preferably said therapeutically effective amount is in a range from about 0.1 mg/kg/day to about 250 mg/kg/day. Even more preferably said therapeutically effective amount is in a range from about 1 mg/kg/day to about 50 mg(kg/day. More preferably yet, said therapeutically effective amount is in a range from about 1 mg/kg/day to about 20 mg/kg/day, and most preferably said therapeutically effective amount is in a range from about 1 mg/kg/day to about 10 mg/kg/day.
Another aspect of the present invention is a method of inhibiting tumor growth comprised of administering an effective amount of an inhibitor of thioredoxin activity to a patient in need thereof. Preferably, but certainly not a requirement, is that the agent also prevents inhibition of apoptosis. The method of inhibiting tumor growth involves administering the inhibitor in the therapeutically effective amounts described above.
Finally, the present invention relates to a method of treating a diseased state comprised of administering a therapeutically effective amount of an agent which inhibits thioredoxin activity wherein said agent has a predetermined acceptable IC50 TR/Trx as described above.